Improvement in derricks



2 Sheets--Sheet 1.

.1. E. SERRELL.

De'rricks.

Patented September 9,

Derricks.' N0. 142,740. Patented September9,1873.

ivrTED STATES PATENT OFFICE.,

JAMES sEnnELL, or NEW YORK, n. Y.

IMPROVEMENT IN vDERRICKS.

Specification forming.,r part of Letters Patent N0.142,740, datedSeplember 9, 1873; application filed i August 16, 1873.

To all whom it may conce/ra:

Be it known that I, JAMES E. SERRELL, of the city and State of New York,have invented Improvement in Derricks for Poising, Raising, Lowering,and Dragging Weights, of which the following is a specification:

It is now usual in the construction of derricks to have the boomattached to the mast, and to swing upon or around with the mast, whichmast is sustained by four or more guys attached to a cap or plate,through which a journal passes, and allows the mast and boom to turnaround as required; but in case of one of these guys breaking the entirederrick is almost certain to fall, and the consequences are often fatalto the workmen attending the same.

The object of this invention is to dispense with guys by use of abalance-weight, that is raised by the weight to be lifted in such amanner that it will hang balanced without lateral strain upon the mastor central sup-- port. The boom of the derrick is hung from a cap at theupper end of the mast. This boom is made double, and the parallel piecesare outside and swing free from the mast. When the weights at each endare not equal, the boom swin gs eudwise until the equilibrium isobtained. l make use of a counterpoise, hung from the mast-head, anddrawn outwardly and upward by the strain of the rope or chain employedto raise the weight. Vhen applying power to raise the weight, thiscounterpoise is drawn gradually outward 'and upward until its weight andleverage upon the boom are equal to the weight to be raised; then suchweight is raised or lowered perpendicularly, or nearly so, and inlowering the weight the parts are so balanced that a stone or otherarticle can be moved with facility by 'hand or other means, slightly upor down, to position the same or bed it'in the mortar, and after thestrain on the hoistingline is decreased by the further slackening of theropes of the derricks the counterpoise swings downward and inwardlytoward the base of the mast until the strain is relieved.

In the drawing, Figure lis a side view; Fig. 2 is a view at right anglesto Fig. 1 of said derrick; and Fig. 3 is a perspective view of amodifica-tion of said derrick.

The mast a is suitably supported at thev base, and at the upper end is acap-piece,b, upon a pintle, so that the cap and parts supported by itcan be turned around. The boom d is made of two poles or bars unitedtogether at the ends, so as to pass freely at each side of the mast a.;and o c are sustaining rods or chains passing from the ends of the boomd to the cap-piece b, so as to suspend such boom d from the cap, and atthe same time allow an eudwise movement to such boom dto vary therelative lengths that the boom projects at the opposite sides of themast, in order that there may be a perfect counterpoise between theweight f to be lifted and the counterpoise g, for the reason that ifboth weights were the same and simultaneously raised, and at equaldistances from the center of the boom, such boom would remain level; butif one weight is greater than the other there will be an endwise motionof the boom until the leverage produces an equilibrium at the time theWeight required to be lifted is first raised off the ground. i

I avail of this mode of balancing the weight to be raised by moving thecounterpoise away from the mast to a greater or less distance. Thecounterpoise g hangs by the slings Z from the cap b, and a guide-collar,a, may be used around the mast, if desired. The rope o, that is used toraise the weight, is attached to the boom at 2, passes through the block3 of the counterpoise, over the pulley 4, thence by the pulleys 5 and6to the pulley 7 of the weightf,

back again through the pulley G, and by the pulleys 9, 8, 5, and l0, toany suitable hoisting mechanism, such as a winch-barrel, p.

lt will be evident that the rope or chain o is under nearly the sameactual tension throughout 5 hence itwill act to draw the counter- @poiseg away from the mast d until the resistance thereof is sufficient tostrain the rope o enough to lift the weightf, and thus a counterpoise isattained of the weight required to be raised, and any weight can beraised within the capacity of the apparatus.

It is to be understood that when a counterpoise is effected, then theweight can be raised and lowered vertically, as illustrated by dottedlines. The weight raised often has to be drawn iu toward the base of thederricl. This is effected by the chain or rope 15 passing through thepulleys 17 and 9 and connecting with the pulley 7 at the weight. Bythese means the weight can be lowered at any point within the rangedescribed by the boom d; and it will be evident that the equilibriumwill be maintained and the counterpoise will descend nearer to the mastas the leverage distance ofthe weight from the mast is lessened.

For quarrying and hoisting materials into buildings I use the form ofderrick shown in Fig. 3, which has not any hoistin g-line attached tothe counter-weight, the counter-weight balancin g and swinging accordingto the relative weight which is to be lifted. I also use a mastsupported in a movable box which can be taken apart for transportationor put together and loaded with stone or other weight, or the mast canbe held in place between the beams of a building in progress and raisedwith each story. The block a3 is, connected by the bridle b3 to the baseof the mast a, and the ropes from the derrick pass through this block tothe weight f, so that the weight can be dragged along without anytendency to injure the mast,

and when the weight is raised the bridle will swing up with it whilebeing lifted upon a cart or truck.

The mode of constructing the mast and double boom can be variedaccording to the ases to which the same are to be applied. l It ispreferable to allow the counterpoise g to rest upon the platform t whenthe derrick is not in use, so as to prevent continued strain on the topof the mast.

If the counterpoise g is attached or suspended at one end of the doubleboom, it will ne moved with that boom to a greater or less distance fromthe mast, according to the weight that is raised, the parts coming to anequiliorium or balance.

The double boom allows all the ropes to pass between it and free fromeach other, and also free from the mast and boom.

When this derrick is mounted on4 wheels adapted to a railway-track, thearticle raised .nay be lowered upon the platform. In this `ase thecounterpoise will balance the weight raised, and swing inwardly and restupon the platform as the weight is lowered.

With aweight suspended either from a der` rick upon a car-platform, orunder any other circumstances, the attendant can, by the exercise ofvery little power, draw upon the rope 15 until it is of such a lengthbetween the pulleys 7 and 9 that it will draw the weight in and cause itto rest upon the platform as the rope o is slackened. Of course the rope15 has to be made fast after it has been adjusted, before the weight islowered, and the weight is gradually transferred from o to 15 until theweight hangs by the rope 15 against the mast or is landed upon theplatform.

In cases where the derrick is upon a platform-car the said car may beweighted sufficiently to render the derrick steady, and the rope o maypass off to astationary engine. In this case the wheels of the car willrequire to be blocked while the weight is being raised. The car may bedrawn along by this rope or chain o by clamping the same, or otherwiseconnecting the same with the platform.

The counterpoise applied in connection with this derrick in the mannershown may be availed of as a means for indicating the weight of thearticle raised. For this purpose a dial or index applied upon the boommay be employed to denote the weight raised, according to the positionof the `counterbalancing-weight.

The counter-balance may be of any suitable material, but with iloatingderricks it will be preferable to employ water in a box or vessel, sothat it may be easily emptied when not in use, or lled more or less,`according to the purpose to which the derrick is to be used.

I claim as my invention- 1. A derrick, made with a double boom passingat each side of a vertical mast and suspended from a saddle that restsupon the top of the mast, in combination with a counterpoise to balancethe weight, substantially as set forth.

2. A counterpoise suspended from the top of the mast, in combinationwith a boom and blocks or pulleys arranged substantially as set forth,so that the weight of the article raised shall act to draw thecounterpoise upward and away from the mast until an equilibrium isobtained, substantially as set forth.

3. A block connected by a bridle to the base of the mast, in combinationwith the hoistingtackle, double boom, and counterpoise, substantially asand for the purposes set forth.

Signed by me this 17th day of July, A. D.

JAMES E. SERRELL.

Witnesses:

GEO. T. PINCKNEY, GHAs. H. SMITH.

